The invention concerns a device for determining parameters of, in particular, therapeutical compression means on limbs, comprising an anatomically modelled limb to which the compression means can be mounted, wherein the limb has sensors for receiving the parameters to be determined.
Compression means of this type may e.g. be so-called “compression socks” or “compression tights”, in general socks or tights having a certain supporting effect, but also corresponding, mostly tubular structures for the arm region, where such measures are used e.g. after breast operations in order to prevent or treat accumulation of liquid in the arms. Such compression means may also be obtained using flat materials, such as e.g. bandages or dressing material, which are applied to the desired limb for compression. These products are mainly knitted fabrics, wherein it is decisive for the success of the therapy, that the pressure on the body surface is sufficient but not too high. The level of compression pressure depends, in particular, on the properties of the material, the processing or production technology and the technique of application. The measurement of parameters, in particular, the applied compression or pressure is advantageous for the production or development of such compression means, but may also be used e.g. to train patients wearing such compression means, or to train the medical and therapeutical staff. The point pressures that result in dependence on the radius of the underlying structure can be theoretically calculated through tensile force relationships of a specific compression material and application of the Laplace formula. This applies to cylindrical and rigid bodies.
A plurality of rigid systems of this type have been described in prior art. U.S. Pat. No. 6,334,363 B1 describes e.g. a device for measuring pressure points through therapeutical compression means, wherein a plurality of sensors are provided which are disposed on the surface of the rigid mold that corresponds to a leg. A pressure profile of the compression means can be generated through simultaneous measurement of the pressures at all measuring points and the plurality of measuring points.
U.S. Pat. No. 4,137,763 moreover discloses a rigid system which also detects pressure values at a plurality of measuring points.
The lower leg or arm of a person, which are the main fields of application of the compression means, are neither cylindrical nor rigid. Depending on the characteristics of the muscles and the mobility of the upper ankle joint or knee, the muscle bellies are shifted during muscle contraction, e.g. during running/walking. This leads to a dynamic system, wherein the perimeters on the lower leg change approximately cyclically with each step.
This influences the resulting pressures under a compression means which change in accordance with the step cycle. When the muscle is relaxed, this is called a resting pressure and when it is contracted, a working pressure. The ratio between resting and working pressures of a compression means is the value which is decisive and characteristic for the clinical efficiency of the therapy.
EP 1 118 851 A1 discloses e.g. a first approach for improving such devices, which discloses a device for measuring the compression through hosiery, wherein a lower rump is provided from individual tubular elements which are partially formed from shells, wherein the shells can be spread apart in order to model legs having a varying thickness in their longitudinal direction. In this fashion, initial elastic properties of hosiery can be measured. However, the model of anatomical movement is disadvantageously oversimplified due to the individual tubular elements, and simulation of a motion sequence by mechanically opening the tubular segments is also inadequate.
GB 2,168,156 A1 also discloses spreading apart, however, for adjusting the measuring body to hosiery to be measured.
In another conventional fashion, measurements concerning the dynamic pressure behavior are performed on human beings by disposing pressure sensors onto the skin. The patients were provided with a corresponding compression were instructed to run on a running belt while the pressures were continuously measured. Such measurements are indeed close to practice but can normally only be reproduced or transferred with great difficulty.
Due to the fact that there is great variance between the two legs of a single person, from day to day, or even throughout the day, even repeated measurements can approach the precise desired value in vivo to only a limited degree.
It is therefore the object of the invention to provide a device of the above-described type which permits reproducible, quasi-continuous measurement of pressures of compression means both in a static and also dynamic fashion.